1. Field of the Invention
This invention relates to gels prepared from novel anionic block copolymers of aromatic vinyl compounds and conjugated dienes.
2. Background of the Art
The preparation of block copolymers of aromatic vinyl compounds and conjugated dienes is well known. One of the first patents on linear ABA block copolymers made with styrene and butadiene is U.S. Pat. No. 3,149,182. Such polymers are broadly termed Styrenic Block Copolymers or SBC's.
SBC's have a long history of use as adhesives, sealants and gels. A recent example of such a gel can be found in U.S. Pat. No. 5,879,694. With the increased use of oil gels, the need for improved properties continues to exist. Such gels may also be used, for example, as a water proofing encapsulant/sealant for electronics and in wire and cable applications. Many gels have deficiencies in their properties, such as too low of a low softening point that limits certain end-use applications. Accordingly, it would be helpful to have gels which when molded have an appropriate hardness, but will not soften at use temperatures.
Applicant has found that certain new and novel polymers will allow the preparation of improved oil gels. In particular, the gels containing the presently claimed high molecular weight polymer composition have much higher ring & ball softening point than oil gels at the same gel hardness (i.e. same polymer content)—the prior art gels being based on similar polymers but having a lower molecular weight.